1. Field of the Invention
The present invention relates to a marketing research system for substituting a stored television program for a scheduled television program and more particularly, to such a system wherein the substitute television program is transmitted to a cooperating household over a telephone line from a central office.
2. Description of the Prior Art
In order to collect market research data, systems are known that automatically monitor the televisions in the households of cooperating panelists. These systems typically monitor the on-off state of a television and identify the channel being viewed. This information is typically accumulated over an entire broadcast day and stored in a small computer installed in each cooperating household wherein the computer organizes the accumulated information for transmission over telephone lines at the end of a broadcast day to a central computer. Examples of such systems are disclosed in U.S. Pat. Nos. 3,651,471; 3,742,462; 3,742,463; 3,772,649; 3,973,206; 4,025,851; and 4,048,562. These systems, however, lack flexibility in that they cannot accommodate substitute programming to permit the testing of viewer's responses to substitute commercials.
Systems are known in which a substitute television signal is broadcast over VHF or UHF as shown in U.S. Pat. No. 3,639,686. Other known systems transmit a substitute television signal via a microwave transmitter or satellite transponder as shown in U.S. Pat. No. 4,630,108. Systems for transmitting substitute television signals over one or more unused cable channels in a cable television network are also known as shown in U.S. Pat. Nos. 4,331,973 and 4,331,974. However, each of these systems requires a broadcasting station to transmit the substitute television signals at the time in which the signals are to be displayed on a television. The operation of such broadcasting stations is very costly.